1. Field of the Invention
This invention relates to an improved, manually actuated, hydraulic device to provide a penile erection for human males who suffer the dysfunction of erectile impotence.
2. Description of the Prior Art
The normal male achieves an erection when a multitude of small blood vessels within a long cylindrical section on each side of the penis called the corposum cavernosum fills with blood as a result of an increase in the vessels' output resistance to blood flow. There are two such parallel cylinders in the penis (the plural being the corpora cavernosa) which simultaneously become engorged with blood thereby producing a penile erection. Unfortunately, there are 10 million men, in the United States alone, who are unable to achieve a penile erection.
There are many causes for impotency in the human male, both psychological and physiological. Among the physiological causes are: long term diabetes, damage to the spinal cord, multiple sclerosis, a surgical procedure in the lower abdomen that has caused nerve damage in the genital region, and advanced age. Such impotence often destroys the male's psychological well being, and often seriously disrupts or even causes the dissolutionment of otherwise fulfilling relationships. It therefore is not surprising to find that the patent art is replete with examples of artifical penile erection devices.
One of the earliest prosthetic devices whose object was to achieve a penile erection is described by Henderson in U.S. Pat. No. 1,133,958 (March 1915). This device suggests the use of an external truss to stiffen the penis by preventing the back-flow of blood. Since the truss is removable, it is a simple matter to obtain a normal flaccid state. However, the external truss mechanism also prevents in-flow of blood and, therefore, cannot provide the five conditions required of a normally erect penis; namely, during erection the penis should become longer, thicker, harder, stiffer, and have a generally upward angle.
Kalnberz, in U.S. Pat. No. 3,832,996 (September 1974), describes two stiff rods designed to be implanted in the corpora cavernosa to attain a penile erection. Although this system provides a longer, thicker, and stiffer erectile state, it does not provide a generally upward angle, and the flaccid state is no longer achievable.
An improved rod is described by Barrington in U.S. Pat. No. 4,151,840 (May 1979), which rod provides a longer, thicker, and stiffer erectile state. Furthermore, the device can be bent downwardly by hand to achieve the flaccid condition. However, in the flaccid condition, the penis is just as long and thick as in the erectile state; also, it is unnaturally stiff and hard.
A manually actuated fluid driven system is described by Strauch et al in U.S. Pat. No. 3,853,122 (December 1974). A serious difficulty in the Strauch et al system is that only a single inflatable, cylindrical stiffener is envisaged. To be effective, there must be stiffeners in each one of the two corpora cavernosa. If the stiffener is in only one corposum cavernosum, the erectile state of the penis will be badly distorted. Furthermore, with the Strauch device, fluid exits the region of the penis through a metering means not under the control of the implantee. The penis therefore could become flaccid too quickly, or could take an unreasonably long time to become flaccid, all depending upon the configuration of the metering means.
Buuck, in U.S. Pat. No. 3,954,102 (May 1976), describes a manually actuated, fluid driven, inflatable penile prothesis with two cylinders in the corpora cavernosa. The Buuck prosthesis achieves the erectile goals of a longer, thicker, harder, and stiffer penis with a generally (though not certainly physiologically sufficient) upward angle during erection, and also provides a physiologically normal flacid state. However, this device still has certain major shortcomings. For example, when the penis is in the erectile state, its upward angle may not reach that achieved in a normal male. Further, the pump and release valve are located in the scrotum, which is one of the body sites most disposed to post-operative discomfort and infection. The Buuck device requires multiple strokes of the pump within the scrotum to achieve an erection, which could require one or more minutes of pumping, especially if the patient is not particularly skilled in pumping a small bulb located within the scrotum. Furthermore, the release valve in the scrotum must be held for on the order of ten to fifteen seconds to return the penis to the flaccid state. Also, a comparatively large reservoir is required by Buuck because fluid cannot be added after implant without surgical intervention; and as a consequence of the large reservoir and small displacement pump used by Buuck, it is possible to permanently distend or even rupture the stiffener cylinders by excessive pumping. Additionally, because of the many separate pieces of tubing and other parts required by the Buuck device, it is necessary to fill and then assemble the many separate parts during the surgical implant; this is a time consuming (and therefore costly) procedure.
A further element of the prior art is U.S. Pat. No. 4,009,711 (March 1977) which issued to Uson, and which describes a non-distensible portion of a stiffener cylinder that is placed in the root of the corpus cavernosum, and a distensible portion that is located within the pendulous portion of the corpus cavernosum. Although there may be valid reasons to provide a structure such as that described by Uson, it is disadvantageous to have a considerable portion of the stiffener cylinder located within the root of the corpus cavernosum if it is not pliable and distensible. In this regard, some shortcomings of the Uson device are that the penis does not feel natural in the flaccid condition because there is a rigid object just beneath the skin at the base of there penis. Furthermore, the shape of the penis in the flaccid condition is not physiologically normal, nor is there stress relief provided for the elastomer stiffener cylinder during the flaccid state (which is most of the time) because the cylinder does not begin its downward curve while still supported within the root of the corpus cavernosum. Additionally, a greater extended length of the penis in the erectile state cannot be achieved because the cylinder does not begin its extension within the root of the corpus cavernosum.